Java getDate 0000/00/00 return strange value

Question

Why does this happens? For the month and day, I think Java is assuming the previous valid month and day, but I don't understand why year is 2.

SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd");
Date result = sdf.parse("0000/00/00");

System.out.println(result.toString());

Output is:

Sun Nov 30 00:00:00 GMT 2

Answer 1

The Gregorian calendar does not have year 0.

Year 0 corresponds to 1BCE (Before Common Era, also known as BC).

Because you supply 0 for the month and 0 for the day, it rolls back to the previous month and previous year.

I.e. 30-Nov-0002 BCE.

Date#toString does not include BCE / CE suffix. It would be superfluous in the vast majority of cases.

If you are going to work with dates that far back then you need to consult with an historian.